A solid writing material using a reversible thermochromic composition that can memorize enantiotropically the states before and after a color change in a certain temperature range such as normal temperature has been heretofore proposed (for example, Patent Literature 1 to 3).
The solid writing material creates script which causes color change according to a temperature change, by using a reversible thermochromic composition singly or the same encapsulated in a microcapsule as a colorant to be added into a wax, namely an excipient. In particular, when a microcapsuled pigment encapsulating a thermal color extinction type reversible thermochromic composition is used, the script can be easily decolored by frictional heat, and therefore it can be used as a highly convenient writing instrument allowing easy correction of written information, etc., and can be applied, for example, to writing in a notebook or a memo book, or to drawing. In such a solid writing material, additives such as a resin are considered besides excipients for use for the purpose of enhancing its strength, but depending on the resin, its use is problematic, for example, because it may adversely affect the color changing property of the reversibly thermochromic composition, and examples of such a problem include inadequate color changing and color extinguishing of script and reduced temporal stability of script, which means, for example, that the script changes or develops color again after its color is once changed or extinguished.